This invention relates to an endless tow device particularly adapted for towing people over snow and/or ice covered surfaces. Alternatively, it may be used for towing people over any low frictional surface such as ice or water.
In the operation of outdoor recreational areas, particularly winter resorts, elaborate structures are provided for transporting skiers up slopes. The cost of such structures, whether T-bars, chairlifts, or gondolas, are such that they can only be economically used for selected slopes and trails.
There are many instances where tows would be advantageous, such as beginners' slopes and moving upwardly and across from one trail to another. However, it is not economical to install the currently available tows for such limited use.
My invention provides a tow, easily made portable, which is eminently useful for the above-described situations, and which is extremely economical.
In the invention, disclosed in my parent application, an endless knotted tow line was provided which line was made from any suitable material such as manilla, sisal, polypropylene, nylon, etc. The drive for the tow line comprised two inflatable resilient tires, each rotatably secured to a frame. The tires were disposed one above the other, their bearing surfaces in frictional engagement. The cord passed through the contacting surfaces in a direction substantially normal to the axes of rotation of the tires. The tires were inflated such that the knotted portions of the cord passed without being deformed. This also allowed the contacting surface areas to remain substantially uniform. In the preferred embodiment, one of the tires was driven and the other tire was idle. In the practice of the invention disclosed in my parent application it was found in practice that ice and/or snow tended to accumulate on the tow line. This resulted in slippage and faulty operation.
In the present invention resilient tires are again used. However, one of the tires, preferably the drive tire, is substantially rigid in reference to the idle tire it engages. Further the bearing surface of the rigid tire is characterized by a plurality of ridges. The resiliency (softness) of the idle tire is adjusted such that the ridge elastically deforms the idle tire. The tow line passes over the ridges and into the deformation and is clamped therebetween. This results in the tires functioning as gears. The tow line is driven through the tires both by the frictional engagement of the bearing surfaces and by the clamping action.
The tow line preferably is knotted.
Alternatively, both tires may be driven, or the soft tire be driven and the rigid tire be soft.